The invention relates to a color television transmission and data storage system, respectively, with time-division multiplex encoding, the system comprising a data generator, at least one data receiver and a transmission or data storage channel, respectively, arranged between the generator and the receiver, this data generator comprising a signal source for producing signals containing luminance, chrominance, synchronizing and identification information and an encoding circuit for time-division multiplex encoding of at least a portion of the signals, after having been or not having been subjected to time compression, this encoding circuit having an output for supplying a time-division multiplex encoded signal for transmission via the transmission channel or storage in the data storage channel, respectively, the data receiver comprising a decoding circuit coupled to the channel and being, as it is, in essence, complementary to the encoding circuit, suitable for supplying signals containing at least luminance and chrominance information which largely corresponds to the data produced by the signal source in the data generator, and to a data generator and data receiver suitable therefor.
Such a system for, more specifically, transmission is described in a public report "Experimental and Development Report 118/82", published by the English "Independent Broadcasting Authority", (I.B.A.), entitled "MAC; A television System for High-Quality Satellite Broadcasting". The report describes several variants of a so-called MAC (Multiplexed Analogue Component) picture coding. As can be seen from a Table on page 9 of the report, it holds for all the variants that in the data generator, which is in the form of a transmitter, the luminance and the chrominance information are each subjected to time compression, the time compression for the chrominance information being twice as large. Of the chrominance information, which comprises two components per line period, one of the two is alternately contained in the time-compressed form in the time-division multiplex encoded signal. In this signal the luminance information associated with each line period is present in the timecompressed form. The report mentions the factors 2/3 and 3/4 for the time compression for the luminance information and time compression factors equal to 1/3 and 3/8 for the chrominance information. The picture information per line period in the time-division multiplex encoded signal is sequentially composed from the time-compressed luminance information and one of the two time-compressed chrominance information components associated therewith.
In the receiver, the time-division multiplex encoded signal is derived from the signal received via the transmission channel, more specifically, the satellite connection, and applied to the complementary decoding circuit which, with the aid of the synchronizing and identification information, produces a time decompression for the luminance and the chrominance information and then repeatedly supplies the decompressed chrominance information over the next line period.
In the transmission channel which, in this example, is a satellite connection, there is a limited bandwidth for the transmission of the picture data. Depending on the proposed variation, bandwidths of 8.4 MHz, 7.5 MHz, and 6.0 MHz are mentioned in the report. For the transmission channel bandwidth of 8.4 MHz a time compression factor of 2/3 is proposed for the luminance information, so that for the bandwidth of the non-compressed luminance information, a bandwidth of 5.6 MHz is obtained. For the available picture data channel bandwidths of 7.5 and 6.0 MHz, a luminance time compression factor of 3/4 is proposed and for the bandwidths of the non-compressed luminance information, the values of 5.6 MHz and 4.5 MHz result. It has been found that for the proposed variants with the limited transmission channel bandwidth at the proposed structure of the time division multiplex encoded signal to be transmitted, frequency limitation for the luminance and the chrominance information are required.
In the foregoing, a transmission channel in a form of a satellite connection is mentioned by way of example. The frequency limitations required for the data transmission with limited bandwidth also occur with a data storage channel having a limited bandwidth. Such a storage channel comprises data storage and data reproducing equipment, such as, for example, tape and record recording and reproducing devices.